
<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8"/>
        <title></title>
</head>
<style>
        .one{
                width: 100px;
                height: 100px;
                border:2px solid #000;
                position: relative;
                background-color: #fff;
            }
        .one:before{
                content: "";
                width: 0px;
                height: 0px;
                border: 10px solid transparent;
                border-left-color: #000;
                position: absolute;
                top: 20px;
                left: 100%;
            }
        .one:after{
                content: "";
                border: 8px solid transparent;
                border-left-color: #fff;
                position: absolute;
                top: 22px;
                left: 100%;
            }
</style>
<body>
<div class="one"></div>
</body>
</html>
